The influence of cimetidine pretreatment(100mg/kg, single i.p.) on the hepatic blood flow was investigated using pharmacokinetic parameters of indocyanine green(ICG) in the rat on the basis of hepacc perfusion-limited model. ICG(1mg/kg) was respectively administered via femoral and portal vein to the control and to the cimetidine-pretreated rats. The rate constant K12, K20 and the systemic clearance(CLt) of ICG were significantly(p<0.05) decreased ill the cimetidine-pretrea-to(B rats, but no significant diffirences were observed in hematocrit and liver weight. The biliary excretion rates of ICG were also decreased regardless of the route of administration in the cimetidine-pretreated rats. And also the hepatic blood flow in rats was decreased about $16\%$ by cimetidine. It may be concluded that the decreased hepatic blood flow with cimetidine mainly contributed to the decreased hepatic uptake and the decreased systemic clearance of ICG.